How to pace your swim

Always arriving into T1 exhausted? Fed up of feeling like you haven’t swum your best? Then follow Dan Bullock’s tips for getting to grips with pacing your swim in the excitement of a race


How great would it be to arrive at transition one always feeling fresh and raring to get on with the bike? Regardless of distance and your swim background, this is easier to achieve than you might initially think. And it all comes down to pacing.


How to pace a race  

When asked about pacing a triathlon swim, I think about a sustainable and efficient turn of speed that keeps me competitive but not so exhausted that I’m destroyed for the bike. I also think about an optimum stroke rate to suit both the conditions and the speed I want to swim at. Essentially, pacing involves the ability to change through the gears to make the most of an open-water race. It also means maximising open-water technique so that there’s very little to reduce your ideal pace – too much sighting is going to reduce your speed and upset your pacing, while an inefficient turn around a buoy (for example, doing breaststroke or one-arm front crawl) will slow you and upset your rhythm, leaving you to work harder to get back up to your race pace. 

However, there are four key areas that you can focus on to pace a race successfully: avoid going too fast; avoid going too slow; create a change of pace; and work on a front crawl (FC) stroke that doesn’t tire you out and allows sustainable speed.

With regards to the latter point, regular drills, video review, land-based training, core strength, mobility and flexibility will help. But the key word is ‘sustainable’. Without good front-crawl technique, the mechanics of your stroke will be tiring and leave you with a pace that slows as the race progresses. 

To take control of your swim race, good swim technique is vital and should be addressed first.

How to improve your front crawl breathing

6 ways to improve your triathlon swim technique

Front crawl technique: the key components

How to streamline your swim

However, for the remainder of this feature, we’ll focus on avoiding going too fast or slow, and pace change.

Avoid going too fast

Going too fast is an all-too-common problem that we see in session after session with triathletes who are, by their very nature, competitive people. 

Pretty much every single beginner triathlete goes off too fast in the excitement of the start, thinking that they can sustain such a fast pace. But more often than not they’ll be left feeling tired for the second half because they’re unsure how to relax back down to a comfortable, sustainable race speed. 

Luckily, there are quite a few session ideas you can incorporate into your swim to help avoid this pitfall. Here are three of the most proven methods…

Negative splits

This is where the second half of a swim is swum harder than the first. Start out comfortably before building the back end.
A good workout would be 8 x 200m. Aim for the second 100m to be 10secs quicker than the first.

Heart rate (HR) pacing swims

Instead of holding a set of 100s at 1:40mins and using a send-off of 2mins, swim at 20-30bpm below max, resting until your HR drops to 50bpm below max at the end of each 100m swim. This might give you a better idea of what your race pace feels like.

If you find a heart rate monitor clumsy in the pool, instead check HR with two fingers on the carotid artery of the neck for 10secs and then multiply by six. The fitter you become, the more quickly your HR will fall.

Clock work

Get a training partner to time you over 4-8 sets of 100m with 20secs rest after each. How close were you to keeping them within a few seconds of each? Wait until the set is complete before asking for times, to avoid too much ‘pace adjustment’ within the set. Just try to feel the speed being kept similar. Counting your strokes will really help here.

Avoid going too slow

To get a better feel for race pace, here are some ideas that will help you swim at a sustainable race pace that will be challenging yet won’t leave you feeling too fresh in T1 or frustrated that you weren’t more competitive. The key to success in this area is knowing what is a realistic but aggressive pace for you.

Broken swim

A favourite of mine is the broken 1,500m, which we at Swim for Tri ( use as a regular test swim. Swim the following with the stated rest taken between sets…

3 x 200m, resting 30secs after each 200m set
5 x 100m, resting 20secs after each 100m set
8 x 50m, resting 10 secs after each
50m set 

Start the clock and stop the overall time at the end of the last 50m, and then subtract 4:20mins (total rest time) from that figure to get a reasonably accurate 1,500m time. 

There’s not enough rest to fully recover between swims, so tiredness accumulates and a fair reflection of current ability is delivered. We swam this session on the last Joe Beer Tri Camp out in Lanzarote, and 16 out of 26 people swam within 60secs of their personal best 1,500m times.

T20/30 swims 

The idea is to swim as far as you can in 20/30mins and count lengths, which is useful for getting an idea of sustainable pace. With practice, you’ll settle into a rhythm that allows you to finish your swim neither too exhausted nor too fresh.

By going over distance, 20mins would be adequate for most people racing a sprint-distance triathlon; 30mins would cover many racing Olympic distance. Doing this, you get a feel for what level of exertion is sustainable for you.

Change your pace

An ability to change pace will help you not only overtake other competitors, but also help you race at your pace and swim the swim you would like to. After the excitement of the start, it’s essential to relax back into a comfortable pace. Building the second half of a swim naturally will feel good as the body warms up after the shock of the start and the sudden exertion.

Chaingang swimming

In a lane of four to six people, swimmer 1 goes before swimmer 2 pushes off on the person in front’s feet. The ‘gang’ are to swim at a relaxed pace, tight to the lane rope, allowing the person at the back plenty of room to push off and sprint past the ‘gang’ down the middle of the lane. Rotate the lead until everyone has practised in all positions.

Fartlek training

Similar to Fartlek cycling or run training, which puts stress mainly on the aerobic energy system. Swim 1-2km as a continuous three length (3L) FC strong, 1L FC fast.
Don’t allow the three lengths to become too easy – it’s not a swim-down from the fast length – and ensure the speed change on the fourth length is significant.

Building pace

Swim 100m repeats at different speeds, getting faster by the length. Equally useful is the ability to get slower by the length.

For example: 8 x 100m, rest 20secs after each 100m, swum as…

Odd 100s – 1L (25m) easy, 2L hard,
1L sprint 

Even 100s – 2L medium, 1L hard, 1L easy

Warning! An improved awareness of pacing, how to sustain a good pace and how to avoid going too hard or too slow will help you arrive into T1 at your absolute best and ready for a strong bike. Practising these drills will help you become more aware of this key part of your swim ability.



Sub-1hr swim session: Pacing changes

How to pace pool-based swims

How to pace your first sprint distance triathlon